You can use a term query to query field values that exactly match the specified keyword. Term queries function similarly to string matching. If a TEXT column is queried and at least one of the tokens in a row exactly matches the keyword, the row meets the query conditions. The keyword is not tokenized.
Prerequisites
- The TableStoreClient is initialized. For more information, see Initialize an OTSClient instance.
- A data table is created. Data is written to the table.
- A search index is created for the data table. For more information, see Create a search index.
Parameters
Parameter | Description |
TableName | The name of the data table. |
IndexName | The name of the search index. |
Query | The type of the query. Set the query type to TermQuery. |
FieldName | The name of the field that you want to match. |
Term | The keyword that is used to match the field values when you perform a term query. This keyword is not tokenized. Instead, the entire keyword is used to match the field values. If the type of the field is TEXT, Tablestore tokenizes the string and uses the tokens to match the keyword. A row meets the query conditions when at least one of the tokens in the row exactly matches the keyword. For example, if the value of a field of the TEXT type in a row is "tablestore is cool", the value can be tokenized into "tablestore", "is", and "cool". The row meets the query conditions if you specify "tablestore", "is", or "cool" as the keyword to match the value of the field. |
ColumnsToGet | Specifies whether to return all fields of each row that meets the query conditions. You can specify the ReturnAll and Columns parameters. By default, the ReturnAll parameter is set to false, which indicates that not all fields are returned. If the ReturnAll parameter is set to false, you can use the Columns parameter to specify the fields that you want to return. If you do not specify the Columns parameter, only the primary key fields are returned. If you set the ReturnAll parameter to true, all fields are returned. |
GetTotalCount | Specifies whether to return the total number of rows that meet the query conditions. The default value of this parameter is false, which specifies that the total number of rows that meet the query conditions is not returned. If you set this parameter to true, the query performance is compromised. |
Examples
The following sample code provides an example on how to query the rows in which the value of the Col_Keyword column exactly matches hangzhou in the data table:
/**
* Query the rows in which the value of the Col_Keyword field exactly matches "hangzhou" in a table.
*/
func TermQuery(client *tablestore.TableStoreClient, tableName string, indexName string) {
searchRequest := &tablestore.SearchRequest{}
searchRequest.SetTableName(tableName)
searchRequest.SetIndexName(indexName)
query := &search.TermQuery{} // Set the query type to TermQuery.
query.FieldName = "Col_Keyword" // Specify the name of the field that you want to query.
query.Term = "hangzhou" // Specify the keyword that is used to match field values.
searchQuery := search.NewSearchQuery()
searchQuery.SetQuery(query)
searchQuery.SetGetTotalCount(true)
searchRequest.SetSearchQuery(searchQuery)
// Return all columns in the rows that meet the query conditions.
searchRequest.SetColumnsToGet(&tablestore.ColumnsToGet{
ReturnAll:true,
})
searchResponse, err := client.Search(searchRequest)
if err != nil {
fmt.Printf("%#v", err)
return
}
fmt.Println("IsAllSuccess: ", searchResponse.IsAllSuccess) // Check whether all rows that meet the query conditions are returned.
fmt.Println("TotalCount: ", searchResponse.TotalCount) // Display the total number of rows that meet the query conditions instead of the number of returned rows.
fmt.Println("RowCount: ", len(searchResponse.Rows))
for _, row := range searchResponse.Rows {
jsonBody, err := json.Marshal(row)
if err != nil {
panic(err)
}
fmt.Println("Row: ", string(jsonBody))
}
}
FAQ
References
When you use a search index to query data, you can use the following query methods: term query, terms query, match all query, match query, match phrase query, prefix query, range query, wildcard query, geo query, Boolean query, KNN vector query, nested query, and exists query. You can use the query methods provided by the search index to query data from multiple dimensions based on your business requirements.
You can sort or paginate rows that meet the query conditions by using the sorting and paging features. For more information, see Sorting and paging.
You can use the collapse (distinct) feature to collapse the result set based on a specific column. This way, data of the specified type appears only once in the query results. For more information, see Collapse (distinct).
If you want to analyze data in a data table, you can use the aggregation feature of the Search operation or execute SQL statements. For example, you can obtain the minimum and maximum values, sum, and total number of rows. For more information, see Aggregation and SQL query.
If you want to obtain all rows that meet the query conditions without the need to sort the rows, you can call the ParallelScan and ComputeSplits operations to use the parallel scan feature. For more information, see Parallel scan.